Profiles

Christina Hansen Wheat

Christina Hansen Wheat

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Works at Department of Zoology
Email christina.hansen@zoologi.su.se
Visiting address Svante Arrheniusväg 18 B
Room D 548
Postal address Zoologiska institutionen: Etologi 106 91 Stockholm

About me

I am an evolutionary biologist studying how behaviour shapes the life of animals. My interests within animal behaviour are broad, spanning from applied to basic research, including questions on how individuality affects fitness, such as home range size or group dynamics, to how behaviour develops and evolves over time.

To address my research questions I use a mix of approaches involving data collection either in situ or under controlled conditions. I prefer to combine various types of data to understand how behaviour for instance affects life history traits, such as dispersal or reproductive success, or how behaviour and hormonal profiles interact. I also find it useful to utilize databases to access larger data sets, which allows me to ask a wider range of more complex questions.

As a PhD candidate at Stockholm University for the past five years, I have been investigating how domestication has affected behavioural development using wolves and dogs as model system.

Please see my personal homepage for current and previous research projects on wolves and dogs, leopards and swift foxes.

Research

Domestication, a process in which species are selected to live in human-controlled environments, has dramatically impacted the evolutionary trajectories of numerous animal and plant species.

The domestic dog (Canis familiaris) is an excellent study species for asking questions about how domestication has affected behaviour. Domestication of the dog from the grey wolf (Canis lupus) occurred at least 15,000 years ago, making the dog the first domesticated species. Present day dogs live in vastly different environments than wolves, with various factors influencing behaviour on both individual and social scales, and wolf-dog comparisons therefore provide an ideal set-up to address questions on how domestication has affected behaviour.

To investigate how domestication has affected behavioural development, I have worked with juvenile wolves and dogs for the past five years of my PhD, hand-raising three litters of wolves and two litters of dogs under identical conditions. Specifically, we are trying to answer questions of how social behaviour develops over time, and how the development of social dynamics, individuality and hormonal profiles might interact. Data is collected using a mix of approaches such as behavioural observations, behavioural testing, social network analysis and cortisol assays based on fecal samples.

Publications

A selection from Stockholm University publication database
  • Christina Hansen Wheat, John Fitzpatrick, Hans Temrin.
  • Christina Hansen Wheat (et al.).
  • Christina Hansen Wheat (et al.).
  • Christina Hansen Wheat, Wouter van der Bijl, Hans Temrin.
  • 2018. Christina Hansen Wheat, Hans Temrin, Clive Wynne.

    Biologists since Darwin have recognized that domestication, where species are selected to live in human-controlled environments, exerts strong selection on organisms and dramatically impacts their evolutionary trajectories. Across domesticated mammal species, characteristic morphological, physiological and behavioural changes occur simultaneously, as correlated traits, a phenomenon known as the domestication syndrome. Key behavioural alterations are connected with the domestication syndrome, in which domesticated animals express decreased aggression and fearfulness alongside increased sociability and playfulness compared to their wild counterparts. To investigate various aspects of the behavioural implications of domestication, we used the dog (Canis familiaris) and its extant ancestor, the grey wolf (Canis lupus), as our study species. Since we currently lack quantitative confirmation that correlated changes in behaviours follow domestication, we evaluated correlations among sociability, aggression, fearfulness and playfulness in more than 90,000 dogs in Paper I. Contrary to expectations, we found weak support for behavioural correlations in modern dog breeds, but observed exaggerated effect sizes of correlations in ancient breeds. We suggest that while selection on suites of behaviour have been relevant during early dog domestication, a recent shift in selection pressures in modern dog breeds affects the expression of domestication-related behaviours independently. In Paper II we therefore contrasted the expression of sociability, aggression, fearfulness and playfulness during domestication in wolf hybrids and dogs, and found that while wolf hybrids were less playful and overall more fearful than dogs, they were not less social or more aggressive than dogs. Our results suggest that behavioral alterations during domestication do not necessarily occur in concert as predicted by the domestication syndrome and point to an important, but previously overlooked, role of selection on playfulness during the domestication of dogs. Finally, while it has been established that behavioural responses in adult domesticated animals are altered compared to ancestral species, we know little about when such species differences occur. We therefore conducted two studies addressing the effects of domestication on behavioural ontogeny. First, we examined the ontogeny of sociability, playfulness, aggression and fearfulness in wolves and dogs in Paper III and found that while wolves became less social and less playful than dogs at 12 and 16 weeks of age, we found no species differences in the development of fear. Our results suggest that the alteration of behaviours in the domestication syndrome do not develop simultaneously, and that species differences in fear might not occur until later in ontogeny. Then, in Paper IV we present the first extended examination of the development of fear behaviour in wolves and dogs throughout their first 26 weeks of life. We found that while dogs, but not wolves, expressed decreased fear towards novelty with age, this did not result in a species difference in fear response until 26 weeks of age. Our results suggest that differences in fear expression between wolves and dogs occur late during juvenile development and are caused by a loss of sensitivity towards novelty with age in dogs. Together, the four papers in this thesis highlight the need for a re-evaluation of the behaviours hypothesized to be shaped by domestication.

Show all publications by Christina Hansen Wheat at Stockholm University

Last updated: January 8, 2019

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